[CentOS] setting the device queue_depth

Hi,

Due to limitations of our Storage we need to set the device queue_depth to 4. I did this with a script that basically does this: echo 4 > /sys/block/sdft/device/queue_depth.

But after a few minutes it starts to grow until it reaches 32 again. What could cause that behavior?

Furthermore the system doesn' t load my qlogic options. I have set them to: cat /etc/modprobe.d/qlogic.conf alias scsi_hostadapter1 qla2xxx options qla2xxx ql2xmaxqdepth=4

But the max queue depth is cat /sys/module/qla2xxx/parameters/ql2xmaxqdepth 32

Any help would be appreciated.

Centos: CentOS release 6.3 (Final) Storage: DDN 9900 Qlogic: 2560 (using distri firmware)

Cheers

Axel